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Acne and sun

Released by Dr. Florence Poli the 2015-11-7

It is often said that acne improves in summer and gets worse in winter. The autumn inflammatory flare-up is dreaded by all acne sufferers.

Has this been proven?

One study reports that in summer, 60% of acne sufferers see an improvement, 20% a worsening and 20% no change in their acne. In other studies, no improvement or change is reported in the summer, and for others acne even gets worse at this time! In my experience, in most cases, adolescent acne improves in the summer and reappears after the holidays. However, for some women acne worsens with sun exposure in the form of inflammatory acne on the forehead and chest.

Why does Acne improve in the sun? 

Tanning tones down redness and the sun’s rays reduce inflammation, so acne becomes less visible. In addition, the sun’s rays reduce bacterial growth on the surface of the skin and in the deep sebaceous glands. In fact, P.Acnes, one of the bacteria responsible for acne, is capable of producing large quantities of intra-cellular porphyrins, substances which – when exposed to the sun’s rays – undergo photo-activation, helping kill the bacteria. It is based on this principle that people with resistant acne are offered laser treatment or phototherapy, since the light rays or laser beams destroy the bacteria.

The skin defends itself from the sun by tanning and thickening. At the end of summer, acne lesions are sometimes less visible on this thick and pigmented skin, but this is merely a cosmetic effect of the sun!

Lastly, the feeling of well-being that sun exposure and holidays bring can be an improvement factor in itself, by reducing a person’s stress levels.

Why does Acne get worse in the sun?

There are multiple reasons why acne worsens under the effect of the sun. If patients are to be believed, heat and humidity are determining factors. When humidity and sweating increase, the skin’s cells swell and block the pilosebaceous follicles. The result? Sebum can no longer flow out. Sebum secretion also increases with heat, becoming more fluid. The sun’s rays cause the superficial layer of the skin to thicken, which encourages the formation of new comedones (black heads). Lastly, the repeated advised application of sun creams or moisturizing and soothing emollient creams can play a role in the formation of comedones by blocking the orifice of the pilosebaceous follicle. In some cases, acne can worsen and flare up because a person needlessly stops their treatments during the summer

What can we advise?

It is a mistake to think the sun is a friend to acne sufferers. We therefore advise sufferers not to overexpose themselves to the sun in the belief they are treating their acne. It is important to continue using acne treatments during the summer to reduce the risk of a relapse or aggravation of acne when summer is over and the sun will no longer be playing its anti-inflammatory role. Some oral treatments may be reduced or changed because they are photosensitising (i.e. not compatible with sun exposure). All local treatments applied in the evening should be continued. Sun protection with non-comedogenic products (those which don’t encourage the formation of black heads) or those specifically for acne-prone skin can be invaluable.